Compatibilized blends of olefin polymer and nitrile rubber are known, U.S. Pat. No. 4,299,931. Although these blends exhibit useful properties, they are not suitable for applications involving low and high temperature exposures. Olefin polymers and acrylic ester copolymer rubber are not very compatible with each other. Their lack of compatibility prevents the development of optimum properties in blends of these materials. Thus, if the compatibility of the blend components can be increased, improved blends may be obtained which can be used where they are subjected to low and high temperature environments.